Surgical apparatus for applying surgical fasteners

ABSTRACT

A self contained gas powered endoscopic surgical apparatus is provided for placing lateral lines of surgical fasteners into body tissue. The apparatus includes an anvil member and a surgical fastener cartridge member mounted to the distal end of an elongated endoscopic portion. A tubular collar of the endoscopic portion moves distally to engage the anvil member and bias the anvil member and the cartridge member into cooperative alignment, thereby clamping body tissue to be fastened between the anvil member and the cartridge member. A self contained pneumatic system is optionally disposed in the surgical apparatus and is actuable to eject and/or form the surgical fasteners in the clamped body tissue. The apparatus further comprises a locking structure for preventing firing of the instrument after it has been fired a predetermined number of times. A counter for displaying the number of times the apparatus has been fired may be provided. A firing interlock is also shown which prevents accidental actuation of the firing trigger. A clamping interlock is shown which prevents approximation of the jaws when the jaws are either misaligned or improperly inserted into the instrument. The instrument also includes structure for disabling the actuation system after a cartridge has been fired and structure for identifying a cartridge member having firing characteristics compatible with the pneumatic actuation system.

This is a divisional of U.S. application Ser. No. 08/134,239 filed Oct.8, 1993 now U.S. Pat. No. 5,487,499.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to surgical stapling apparatus, and moreparticularly to surgical apparatus to perform sequential operations suchas tissue clamping, staple forming and/or tissue cutting.

2. Description of Related Art

Surgical stapling apparatus is known wherein tissue is first grasped orclamped between opposing jaw structure and then fastened by means offasteners. In some instruments a knife is provided to cut tissue whichhas been joined. The fasteners are typically in the form of surgicalstaples; however, two part polymeric type fasteners are also known.

Instruments for this purpose can comprise two elongated fingers whichare respectively used to capture or clamp tissue. Typically, one of thefingers carries a disposable cartridge housing a plurality of staplesarranged in at least two lateral rows while the other finger comprisesan anvil for curling the staple legs into hook form upon their beingdriven against the anvil. The stapling operation is effected by a cambar which travels longitudinally along the cartridge carrying finger,acting on transversely mounted pushers which in turn act upon thestaples to place rows of staples in body tissue. A knife may optionallybe positioned to operate sequentially immediately behind the cam bar andlaterally positioned between the staple rows to longitudinally cutand/or open the stapled tissue between the rows of staples. Suchinstruments are disclosed in U.S. Pat. No. 3,079,606 to Bobrov et al.and U.S. Pat. No. 3,490,675 to Green. The instruments disclosed thereincomprise apparatus for simultaneously making a longitudinal incision andapplying a row of staples on both sides of an incision.

A later development disclosed in U.S. Pat. No. 3,499,591 to Greenapplies a double row of staples on each side of the incision. This isaccomplished by a cartridge assembly wherein a cam member moves within aguide path between two sets of staggered staple carrying grooves. Stapledrive members located within the grooves each have two staple pusherplates, and sloping surfaces disposed within the guide path so as to becontacted by the longitudinally moving cam and be driven along thegroove to effect ejection of two staples.

The cartridge assemblies typically come in a plurality of sizes, eachvarying in wire diameter, staple size and number of staples containedtherein. Depending on the procedure to be performed, the surgeon mustselect the appropriate cartridge assembly.

The instruments described above were all designed to be used in surgicalprocedures wherein surgeons have direct manual access to the operationsite. However, in endoscopic or laparoscopic procedures surgery isperformed through a small incision or through narrow cannulae insertedthrough small entrance wounds in the skin. In order to address thespecific needs of endoscopic and/or laparoscopic surgical procedures,endoscopic surgical stapling apparatus such as that shown in U.S. Pat.No. 5,040,715 to Green et al. have been developed. This apparatus iswell suited for such procedures and incorporates a distal end having ananvil and staple cartridge assembly and a manually operated handleassembly interconnected by an endoscopic portion which permits theinstrument to be inserted into a cannula and be remotely operated by thesurgeon.

The instruments discussed above all require some degree of manuallyapplied force in order to clamp, fasten and/or cut tissue. This manualapplication can prove awkward or difficult depending upon theorientation of the instrument relative to the surgeon, the type oftissue being operated on, the number of staples to be placed or thestrength of the surgeon. Furthermore, because of the difficulty andexpense of cleaning and sterilizing surgical instruments between uses,there is increasing interest in and demand for instruments which aredisposable after use in a single surgical procedure rather thanpermanent and reusable. And because of the greater convenience and easeof using self-powered instruments as well as the more uniform resultstypically produced by self-powered instruments (as compared especiallyto manually powered instruments), there is increasing interest in anddemand for instruments which are self-powered.

Therefore, it is one object of the present invention to provide a selfcontained gas powered surgical apparatus for driving fasteners into bodytissue.

It is a further object of the present invention to provide a selfcontained gas powered surgical apparatus insertable through a smallincision or narrow tube for driving surgical fasteners into body tissueand cutting the body tissue between rows of staples.

Another object of the present invention is to provide a self containedgas powered surgical apparatus which is disposable after use.

A further object of the present invention is to provide a self containedgas powered surgical apparatus having a gas metering element to preventfiring of the staples from the cartridge unless a sufficient quantity ofgas is available to move the driving member through a full sequence ofoperation.

Another object of the present invention is to provide a surgicalapparatus having a clamping lockout mechanism which will preventclamping of tissue unless the cartridge has been properly inserted inthe instrument.

A further object of the present invention is to provide a self containedgas powered surgical apparatus having sealing structure for inhibitingthe escape of gas through the apparatus.

Another object of the present invention is to provide a self containedgas powered surgical apparatus having counter structure for displayingthe number of times the instrument may be fired.

A further object of the present invention is to provide a self containedgas powered surgical apparatus with lockout structure to disable theapparatus after a predetermined number of firings.

Another object of the present invention is to provide a self containedgas powered surgical apparatus having a unique counter mechanism whichindicates the number of times the apparatus may be fried and whichprevents firing Of the apparatus after a predetermined number offirings.

A further object of the invention is to provide a surgical apparatuswhich disables an actuation mechanism in the absence of an unfiredfastener cartridge.

Another object of the invention is to provide a surgical apparatus whichwill disable an incompatible fastener cartridge upon loading to preventfiring of the incompatible cartridge in the apparatus.

SUMMARY OF THE INVENTION

The objects of the subject invention are accomplished in accordance withthe principles of the invention by providing a surgical instrument whichis either manually operated in its entirety or at least partiallyoperable by means of a relatively low pressure pneumatic assembly.Advantageously, the surgical instrument in accordance with an embodimentof the present invention is a surgical stapling apparatus adapted forplacing one or more longitudinal rows of staples. This apparatus mayfurther include a knife for making an incision in body tissue betweenrows of staples. The latter configuration may find particular use ofadjoining two hollow organs or in removing an organ, such as theappendix, the gallbladder, etc.

The surgical instrument of the present invention in an endoscopicstapler configuration comprises a frame; an endoscopic portion defininga longitudinal axis and extending distally from the frame, theendoscopic portion including an elongated housing having a distal memberfor mounting a cartridge assembly. The cartridge assembly includes aplurality of surgical staples slidably mounted therein and has a tissueengaging surface. An anvil member is also provided and has a stapleforming surface and a proximal end mounted to the elongated housing suchthat the anvil member is movable between an open position and a closedposition such that the staple forming surface is in close cooperativealignment with the tissue engaging surface of the cartridge assembly.

The instrument further includes structure for moving the anvil memberbetween the open and the closed positions and structure for ejecting thesurgical staples from the cartridge assembly to cause the staples toengage and form on the staple forming surface of the anvil member. Theinstrument also optionally includes a self contained pneumatic systemwhich is disposed in the frame and includes a supply of relatively lowpressure gas which is connected to a pneumatic actuator mechanism. Thepneumatic actuator mechanism actuates the structure for ejecting thesurgical staples from the cartridge assembly.

The surgical instrument of the subject invention may be constructedeither as a reusable unit or as a single use, disposable unit or,alternatively may be formed with a reusable handle portion andreplaceable staple carrying cartridges. The present inventionadvantageously permits surgeons to perform internal surgical proceduresincluding stapling and/or cutting simply by manually clamping the tissueto be manipulated and either manually or pneumatically actuating the jawmembers. The pneumatic actuation embodiment may result in greaterconvenience and ease of use of the instrument as well as more uniformactuation of the instrument mechanism.

The pneumatically actuated stapler embodiment of this invention ispreferably controlled by a manually operable trigger or other similarcontrol. Momentary operation of the trigger initiates an operating cycleof the stapler which is automatically completed without continuedactuation of the trigger. A safety interlock may also be employed incooperation with the trigger mechanism to prevent accidental actuation.Preferably the stapler performs only one operating cycle in response toeach operation of the control regardless of the length of time thecontrol is operated beyond the time required to initiate an operatingcycle. The stapler will not begin a new operating cycle until thepreceding cycle has been completed.

In a preferred embodiment of the subject invention, a safety mechanismmay be incorporated in either a pneumatically actuated or manuallyactuated apparatus to prevent closure of the jaws if they are misalignedor improperly inserted. In addition, a mechanism may be provided toprevent the user from loading an inappropriate stapling cartridge intothe instrument.

In another preferred embodiment of the invention, the operating cycle ofa pneumatically actuated apparatus will not begin unless sufficient gasremains in the reservoir to propel the instrument through a completecycle. Alternatively, structure may be provided to give a visual ortactile indication of the number of times the instrument has been firedand/or lock out the operating cycle after a given number of firings. Thecounter structure may also be configured to indicate the number of timesthe instrument can be fired. Preferably, the counter structure isoperatively associated with the pneumatic actuation system and willinhibit the actuation thereof after a predetermined number ofoperations.

In another advantageous embodiment of the invention the surgical elementincludes adjustment structure which permits the instrument to beselectively preset to fire in a predetermined sequence to drive a givennumber of staples and/or rows of staples.

Further features of the invention, its nature and various advantageswill be more apparent from the accompanying drawing and the followingdetailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described hereinbelow withreference to the drawings wherein:

FIG. 1 is a perspective view of a self contained gas powered endoscopicsurgical instrument with which the present invention may be beneficiallyemployed;

FIG. 2 is an exploded perspective view of the frame and pneumaticassembly of the surgical instrument of FIG. 1;

FIG. 3 is an exploded perspective view of the endoscopic portion of thesurgical instrument of FIG. 1;

FIG. 3A is a side plan view in partial cut away of the pusher washersand flange member of the pneumatic system in accordance with anembodiment of the surgical instrument of FIG. 1;

FIG. 4 is an exploded perspective view of one embodiment of the anviland cartridge assembly of the surgical instrument of FIG. 1;

FIG. 5 is a side plan view in cross section taken along line 5--5 ofFIG. 1 showing the frame and pneumatic assembly in the unclamped andunfired position;

FIG. 6 is a transverse view in cross section taken along line 6--6 ofFIG. 5 oriented toward the proximal end of the instrument showing theframe and pneumatic assembly in the unclamped position;

FIG. 7 is a side plan view in cross section showing the frame andpneumatic assembly of the surgical instrument of FIG. 1 in the clampedand unfired position;

FIG. 8 is a transverse view in cross section taken along line 8--8 ofFIG. 7 oriented toward the proximal end of the instrument showing theframe and pneumatic assembly in the clamped and unfired position;

FIG. 9 is a top plan view in cross section taken along line 9--9 of FIG.5 showing the frame and pneumatic assembly of the surgical instrument;

FIG. 10 is a transverse view in cross section taken along line 10--10 ofFIG. 5 oriented toward the distal end of the instrument showing aportion of the frame and pneumatic assembly;

FIG. 11 is a side plan view in cross section showing the frame andpneumatic assembly of the surgical instrument of FIG. 1 in the clampedand fixed position;

FIG. 12 is a side cut away view in cross section showing the operationof the pneumatic assembly of the surgical instrument of FIG. 1 as it isfired;

FIG. 13 is a side cut away view in cross section taken along line 13--13of FIG. 12 showing the valve and gas tube of the pneumatic assembly;

FIG. 14 is a side plan view in cross section showing the frame andpneumatic assembly of a surgical instrument incorporating an adjustablestroke mechanism;

FIG. 15 is a side cut away view in cross section of a surgicalinstrument incorporating a metering assembly between the valve andpiston assembly;

FIG. 16 is a side plan view of a channel member of the surgicalinstrument of FIG. 1;

FIG. 17 is a transverse view in cross section taken along line 17--17 ofFIG. 16 oriented toward the proximal end of the channel member;

FIG. 18 is a transverse view in cross section taken along line 18--18 ofFIG. 16 oriented toward the distal end of the channel member;

FIG. 19 is a bottom plan view of an anvil member of the surgicalinstrument of FIG. 1;

FIG. 20 is a top plan view of the anvil member of FIG. 19;

FIG. 21 is a side view of the anvil member of FIG. 19;

FIG. 22 is a top plan view of a cam bar adaptor of the surgicalinstrument of FIG. 1;

FIG. 23 is a side plan view of the cam bar adaptor of FIG. 22;

FIG. 24 is a front plan view of the cam bar adaptor taken along line24--24 of FIG. 22 oriented toward the proximal end of the adaptor;

FIG. 25 is a side plan view in cross section of the cartridge housing ofFIG. 4;

FIG. 26 is a top plan view of the cartridge housing shown in FIG. 25;

FIG. 27 is a side cut away view in cross section of the cartridgehousing of FIG. 25 taken along line 27--27 of FIG. 26;

FIG. 28 is an exploded perspective view of a cartridge assembly of thesurgical instrument of FIG. 1;

FIG. 29 is a perspective view of the assembled cartridge assembly ofFIG. 28;

FIG. 30 is a perspective view in partial cross section of an anvil andcartridge assembly of the surgical instrument of FIG. 1;

FIG. 31 is a perspective view in partial cross section of an anvil inaccordance with the embodiment of FIG. 30;

FIGS. 32 through 34 are side plan views in partial cross section of asequence of operations for the anvil and cartridge assembly of FIG. 30;

FIG. 35 is a perspective view of another self contained gas poweredsurgical instrument with which the present invention may be beneficiallyemployed;

FIG. 36 is an exploded perspective view of the handle portion of theself contained gas powered surgical instrument of FIG. 35;

FIG. 37 is an exploded perspective view of the endoscopic portion andjaw structure of the self contained gas powered surgical instrument ofFIG. 35;

FIGS. 38 and 39 are side cross-sectional views of the firing triggerwith integral lockout in the unfired and fired positions of the surgicalinstrument of FIG. 35;

FIGS. 40 and 41 are side views of the cartridge and support structure ofthe surgical instrument of FIG. 35 showing the operation of the clamplockout structure;

FIG. 42 is a side elevational view in partial cross-section of the frameportion of the self contained gas powered surgical apparatus of thesubject invention which includes a unique counter mechanism forindicating the number of times the surgical apparatus has been fired;

FIG. 43 is a perspective view in partial cross-section of the frameportion illustrated in FIG. 42 with the plunger advanced distally duringa firing operation;

FIG. 44 is a side elevational view in partial cross-section of the frameportion illustrated in FIG. 42 with the counter mechanism indexed inresponse to the firing operation illustrated in FIG. 43;

FIG. 45 is a side elevational view in partial cross-section of the frameportion illustrated in FIG. 42 with the counter mechanism indexedthrough four firing operations to lock the trigger mechanism;

FIG. 46 is an enlarged partial break-away view of the distal end portionof the apparatus;

FIG. 47 is an enlarged partial break-away view similar to FIG. 46illustrating the channel stop engaged with channel stop abutment member;

FIG. 48 is a partial perspective view of a pneumatic actuation system inaccordance with the present invention;

FIG. 49 is a partial perspective view similar to FIG. 48 illustratingthe trigger rod engagement member in position behind the rocking lever;and

FIG. 50 is an enlarged partial perspective view illustrating cartridgeidentifier structure in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

It is generally accepted that endoscopic procedures are more common thanlaparoscopic procedures. Accordingly, the present invention shall bediscussed in terms of endoscopic procedures and apparatus. However, useherein of terms such as "endoscopic", "endoscopically" and "endoscopicportion", among others, should not be construed to limit the presentinvention to a stapling and cutting apparatus for use only inconjunction with an endoscopic tube. To the contrary, it is believed thepresent invention may find use in any procedure where access is limitedto a small incision, including but not limited to laparoscopicprocedures. Also, as used herein the terms "fasteners" and "staples"shall be treated equivalently. Unless otherwise stated, the term"cartridge assembly" shall include at least the cartridge itself andstaples or fasteners and staple drive members disposed therein.

In the drawings and the description which follows, as is traditional,the term "proximal" will refer to the end of the instrument which isclosest to the operator while the term "distal" will refer to the end ofthe instrument which is furthest from the operator.

Although the principles of the invention are applicable to other typesof manually and pneumatically actuated surgical fastening instruments,the invention will be fully understood from the following illustrationof its application to endoscopic surgical fastening instruments,including specifically, but without limitation, apparatus of the typedisclosed, in U.S. Pat. No. 5,040,715 to Green et at., the contents ofwhich are incorporated herein by reference. Also, although the inventionis applicable to surgical fastening apparatus having otherconstructions, the invention will be illustratively described in itsapplication to surgical staplers in which a staple cartridge containinga plurality of staples, staple drivers and staple firing means incooperation with anvil means respectively form opposing jaw structurelocated on a distal end of the stapler for capturing and joining tissue.

As shown in FIG. 1, a self contained gas powered endoscopic surgicalinstrument 50 which may beneficially employ the principles of thisinvention includes a frame 52 and an endoscopic portion 54. An anvil 56and cartridge assembly 58 are mounted in a distal end 60 of endoscopicportion 54 and are preferably interchangeable with other anvil/cartridgeassemblies (as discussed in greater detail hereinbelow) to perform awide variety of surgical fastening procedures as needed.

Anvil 56 and cartridge assembly 60 are manually controlled by means ofan articulating handle 62 in the frame 52. This handle 62 interconnectswith anvil 56 by means of a linkage disposed in endoscopic portion 54such that when handle 62 is moved from its open position (FIG. 1) to aclosed position (FIG. 7), anvil 56 is moved into close approximationwith cartridge assembly 58. This operation will be discussed in greaterdetail below.

Turning now to FIG. 2, an exploded perspective view of the frame andpneumatic system is shown. Frame 52 includes a first housing member 64and a second housing member 66 enclosing a pneumatic system showngenerally at 68. Articulating handle 62 is pivotally connected at adistal end thereof to clamp tube 70 at pivot point 72. Longitudinalgrooves 74 formed in both first and second housing members 64, 66adjacent pivot point 72 slidably receive molded shuttles 76 attached tohandle 62 at 72. The molded shuffles 76 are pivotally connected toeither side of the pivot point 72 on the distal end of handle 62 andserve to guide the distal end of handle 62 in a longitudinally distaldirection as the handle is compressed.

A pair of articulating links 78 interconnect an intermediate portion ofhandle 62 to a pair of projections 80 formed on an upper surface ofhousing members 64, 66 respectively. A handle return spring 82 extendsbetween handle 62 and housing members 64, 66 by means of spring anchorpins 84, one of which is disposed in handle 62 and the other extendingbetween projections 80 which also serve to pivotally connectarticulating links 78 to projections 80. This spring 82 assists inreturning handle 62 from its closed position to its open position.

A pair of articulating links 78 interconnect an intermediate portion ofhandle 62 to a pair of projections 80 formed on an upper surface ofhousing members 64, 66 respectively. A handle return spring 82 extendsbetween handle 62 and housing members 64, 66 by means of spring anchorpins 84, one of which is disposed in handle 62 and the other extendingbetween projections 80 which also serve to pivotally connectarticulating links 78 to projections 80. This spring 82 assists inreturning handle 62 from its closed position to its open position.

The proximal end of handle 62 is preferably diagonally formed away fromhousing members 64, 66 so as to enable the surgeon to more easilyrelease the handle 62 from its closed position. This is done by placingthe hand under the proximal end of the handle and lifting. A texturizedor serrated portion 86 may advantageously be formed on an under surfaceof the proximal end of handle 62 to enhance gripping of the handle 62.

Pneumatic system 68 is wholly contained within housing members 64, 66and includes a container 88 of relatively low pressure gaslongitudinally slidably mounted therein. The pressure of the gas incontainer 88 during operation of the stapler is typically less thanabout 200 p.s.i.g. and preferably in the range from about 80 p.s.i.g. toabout 160 p.s.i.g. Any suitable non-toxic gas can be used including butnot limited to halogenated hydrocarbons which are gaseous at roomtemperature, e.g., fluorinated hydrocarbons such as Freon 12 orchlorinated hydrocarbons such as Freon 152 A. Container 88 dispenses therelatively low pressure gas through stem 90, valve 92 and gas tube 94when the firing trigger 96 is depressed. Spring 97 is positioned betweencontainer 88 and valve 92 and serves to hold the container 88 away fromvalve 92. Valve 92 is fixed within housing members 64, 66 and islongitudinally adjustable by means of set screw 93. (FIG. 13) Thisfeature permits the position of valve 92 to be longitudinally changed tocompensate for manufacturers' variations in length among containers 88between a distal end and the proximal end of stem 90.

Disposed above container 88 within housing members 64, 66 is a pneumaticactuator 98. Actuator 98 includes a pneumatic cylinder 100 which is heldin place by opposing pins 99 and which is closed at its proximal endexcept for ferrule 102 and is open at its distal end, as well as apneumatic piston 104 mounted for reciprocal motion in cylinder 100parallel to the longitudinal axis of endoscopic portion 54. Cylinder 100is preferably circular in transverse cross-section however other shapeswould function acceptably well.

Piston 104 is pneumatically sealed to cylinder 100 by "0" ring 106molded of polyethylene or the like. Gas dispensed from container 88 issupplied to pneumatic actuator 98 via gas tube 94 which admits the gasto cylinder 100 through ferrule 102 behind piston 104 to drive piston104 distally in the cylinder. The distal end of piston 104 is adapted toengage the firing mechanism of the surgical apparatus as will bedescribed in greater detail below.

Referring to FIGS. 2, 5 and 7, firing trigger 96 is pivotally mounted ina proximal end of housing member 64, 66 by pivot pin 108. Spring 110 ispositioned adjacent pin 108 and serves to bias the firing trigger 96proximally into the prefiring position. A trigger rod 112 extendsdistally from firing trigger 96 longitudinally to engage piston slide114 positioned in a lower portion of piston 104. Piston slide 114comprises a substantially "U"-shaped channel which fits into acorresponding groove 116 formed in piston 104. Piston slide 114 isspring loaded in a proximal direction by spring 118 and includes atransverse projection 120 on a lower distal end thereof which engagesthe distal end of trigger rod 112.

Referring now to FIGS. 2 and 5-11 and initially to FIGS. 2, 5-8 and 11,a rocking lever 120 is pivotally mounted on transverse slide pin 122 andis adapted for transverse movement relative to slide pin 122 between anengaged position prior to firing (FIGS. 7-9) and a disengaged positionwhen articulating handle 62 is open (FIGS. 5 and 6). Cam slide 124 isvertically mounted in fast housing member 64 for reciprocal movementbetween an upper and lower position (FIGS. 6 and 8 respectively) andserves to move rocking lever 120 between the engaged position (FIG. 8)and the disengaged position (FIG. 6). Thus, until the articulatinghandle 62 is closed causing cam slide 124 to move rocking lever 120 intothe engaged position, the instrument 50 cannot be fired.

Cam slide 124 is normally biased in its upper disengaged position by camslide spring 126 mounted in vertical groove 128 of first housing member64 (FIGS. 5 and 6). In this upper position, cam slide 124 extends upwardbeyond first housing member 64 (FIG. 6) to engage articulating handle 62as it is moved to a closed position (FIGS. 7 and 8). Cam slide 124further includes a camming surface 130 which contacts a correspondingcamming surface of camming block 132 mounted on slide pin 122. Cammingblock 132 is loaded against cam slide 124 by slide spring 134 and movesrocking lever 120 transversely on slide pin 122 between an engagedposition and a disengaged position. Referring to FIG. 8, as thearticulating handle 62 is compressed toward housing members 64, 66 inthe direction of arrow 135 it contacts cam slide 124 moving it downwardand causes camming surface 130 to move camming block 132 and rockinglever 120 transversely into an engaged position in line with piston 104.

Turning to FIGS. 5, 7-9 and 11, once the articulating handle 62 has beenflatly compressed (FIGS. 7-9) rocking lever 120 is disposed in alignmentwith piston slide 114 and can be pivotally moved about transverse slidepin 122 to engage pusher disk 136 at the distal end of container 88.When the instrument is in the clamped configuration, depression of thefiring trigger 96 moves trigger rod 112 distally in the longitudinaldirection causing piston slide 144 to engage and pivot rocking lever 120which, in turn, engages pusher disk 136 and moves container 88longitudinally into contact with valve 92 to dispense gas and propelpiston 104 in the distal direction. See FIGS. 11, 12 and 13.

As piston 104 moves distally, rocking lever 120 remains in its pivotedfiring position by contact with the bottom surface of piston 104. A gap138 is formed in the bottom surface of piston 104 near the proximal endthereof which gap effectively allows rocking lever 120 to disengage frompiston 104 and pivot back to a position wherein container 88 is releasedfrom engagement with valve 92, stopping the flow of gas into pneumaticcylinder 100.

Return springs 140, 142 disposed in endoscopic portion 54 drive piston104 back to its initial prefired position. A camming surface 144 isformed in a distal end of gap 138 and causes rocking lever 120 to movetransversely out of engagement with piston 104 as it returns proximallyand the rocking lever 120 moves to its original prefired position (FIG.7).

FIG. 14 shows a second surgical instrument which may benefit from thepresent invention which incorporates an adjustment mechanism 146 whichpermits the instrument 148 to be selectively adjusted to change thelength of the firing and return strokes of piston 150. This advantageousfeature permits the user to selectively fire a predetermined length ofstaples using a single instrument. For example, if the user installs astaple cartridge assembly having six rows of staples, each row having alongitudinal length of 60 mm, the instrument is set using adjustmentmechanism 146 to fire the staples in the entire length of the cartridge.Cartridges having some lesser length of staples may be inserted andfired depending on the needs of the user.

The adjustment mechanism 146 shown in FIG. 14 includes a belt 152 whichtravels around a pair of longitudinally disposed pulleys 154, 156. Afirst linkage rod 158 engages the top portion of belt 152 and extends toa gap adjustment member 160 slidably positioned in piston 150. A secondlinkage rod 162 engages the bottom portion of belt 152 and extends to aslidable piston stop 164 disposed within pneumatic cylinder 100.

Belt 152 may be rotated in either the clockwise or counterclockwisedirection by rotating knob 166 disposed in housing 172 between pulleys154 and 156. This permits the user to preselect the firing stroke of theinstrument 148. For example when belt 152 is rotated counterclockwise,the firing stroke piston stop is being driven proximally by secondlinkage rod 162 and the gap 168 wherein the raking lever 120 disengagesthe pneumatic actuator 98 is correspondingly widened. This permits theuser to fire shorter rows of staples without changing cartridgeassemblies. Conversely, when belt 152 is rotated in a clockwisedirection, the firing stroke is progressively lengthened this allowingthe user to fire up to the entire length of the rows of staples in thecartridge assembly.

In the instrument 148 shown in FIG. 14, the firing stroke may be presetto fire either 30 mm or 60 mm rows of staples from a 60 mm lengthcartridge assembly. These preset positions correspond to camming pins186 and 170 respectively which serve to disengage fast rod linkage 158from belt 152 so that belt 152 is not rotated during the firing strokeof the pneumatic actuator 98.

Turning now to FIG. 15, a pressure sensor 174 is disposed in linebetween the valve 92 and the pneumatic cylinder 100 to sense and/orregulate the gas delivered from container 88 to the cylinder 100. Duringsurgical procedures involving the driving of surgical fasteners andparticularly where a knife is used to divide fastened tissue, it isimportant that when the trigger is depressed them is sufficient gasremaining in the container 88 to complete an entire piston firingstroke. If insufficient gas were available, the piston may not be ableto fasten and/or divide the desired length of tissue, necessitatingduplication of the procedure. Pressure sensor 174 serves to premeasurethe mount of gas necessary to achieve the desired piston stroke beforeactivating to permit the gas to flow into the pneumatic cylinder 100 todrive piston 104.

It is also envisaged that a counter mechanism can be incorporated tooperate in conjunction with the pneumatic system 68 in order to monitorthe number of firings which the instrument has been subjected to. Thisnumber can be visually displayed to the operator so that, for example,after a given number of firings, the instrument can be overhauled orreplaced. Similarly, where a relatively small number of firings areavailable from a single gas container, this counter mechanism willassist the operator in recognizing when the container is nearingexhaustion. In a particularly desirable embodiment, the countermechanism can be combined with a lockout mechanism which will disablethe firing mechanism after a preselected number of firings.

As seen in FIG. 15, upon depressing firing trigger 96, gas is releasedfrom container 88 substantially as described herein above. However,after leaving stem 90 and passing through nozzle 92, the gas contactspressure plate 176. Pressure plate 176 is preset by means of spring 178to keep orifice 180 closed until a predetermined gas pressure isrealized at the pressure plate 176. Once this threshold pressure isrealized, pressure plate 176 moves out of contact with orifice 180permitting gas to pass therethrough and into pneumatic cylinder 100 todrive piston 104 distally. In the event that insufficient gas isavailable to reach this threshold pressure, pressure plate 176 continuesto block orifice 180 and the instrument cannot be fired.

Referring now to FIG. 3, there is shown in exploded detail an endoscopicportion 54 of a surgical instrument which may beneficially employ thepresent invention. At a proximal end, piston 104 is longitudinallyreciprocally slidable through clamp tube 70 and extends into theproximal end of cover tube 182. The distal end of piston 104 is providedwith an attachment flange 184 which flange 184 mounts a plurality ofpusher washers 186 thereon. These pusher washers 186 are formed in asubstantially abbreviated frustoconical cross-section from a resilientmaterial such as, for example, commercial spring steel or type 302stainless steel. These washers are typically known as Belleville SpringWashers available through SPEC Associated Spring Raymond, Barnes GroupInc. The washers are especially suited for high loads in small spacesand may be combined in varying sequences to achieve numerous loadcarrying possibilities. In the embodiment of FIG. 3, a total of twelvepusher washers are used substantially as shown in FIG. 3A with duplicatewashers arranged in six opposing sets. A spring support washer 188 ispositioned on flange 184 distal to pusher washers 186 and serves toengage the proximal ends of inner and outer return springs 140 and 142.Lock washer 189 holds the washers in place on flange 184. Attachmentflange 184 has a chamfered distal tip and is configured and dimensionedto be received between the proximal fingers 190 and channel 192.

As shown in FIGS. 3 and 16-18, channel 192 is an elongated structureslidably mounted in endoscopic portion 54 for reciprocal longitudinalmotion therein. As mentioned above, channel 192 has fingers 190 at aproximal end thereof to receive attachment flange 184 of piston 104. Ata distal end of channel 192 there is provided a fork 194 defining a slot196 therebetween. Fork 194 has a pair of opposed ramping surfaces, 198and 200 respectively, the purposes of which will be described in greaterdetail below. Proximal to fork 194 is abutting structure 202 whichstructure extends below the lowermost dimension of fork 194.

Referring back to FIG. 3, an extension sleeve 204 is disposed within thecover tube 182 and is fixed on a proximal end thereof to clamp tube 70.Sealing member 206 is mounted on flange 208 of clamp tube 70 and servesto sealably isolate the frame 52 of the instrument 50 from theendoscopic portion 54. Inner and outer return springs, 142 and 140respectively, are contained within upper extension spacer 210 and lowerextension spacer 212 which are, in turn, fixed within the extensionsleeve 204. Spring support washer 188 abuts the proximal ends of innerand outer return springs 142 and 140 and, when the instrument is fired,transmits the energy of the compressed springs 142, 140 to the piston104, renaming it to its prefired position.

Support structure 214 is also disposed within extension spacers 210, 212and function to releasably receive anvil and/or cartridge assemblies ininstrument 50. Support structure 214 is retained in place withinextension spacers 210, 212 by transverse support key 216. An anvilreturn spring 218 is affixed to an underside portion of supportstructure 214 and assists in the retention of the anvil within theinstrument.

A collar assembly, shown generally at 220, is attached to the respectivedistal ends of external sleeve 204 and extension spacers 210, 212. Thisassembly 220 includes a forward collar tube 222, a collar tube spacer224 and a rear collar tube 226, each having camming bosses 268, 270formed on inner surfaces therein as will be described in greater detailbelow.

In the instrument shown in FIGS. 1-3, the endoscopic portion 54 isrotatable relative to the frame 52 by means of rotation knob 228 (FIGS.1 and 2). This rotation knob 228 is in the form of an abbreviatedfrustoconical structure having a bore therethrough dimensioned toreceive a proximal end of cover tube 182. At a proximal end of knob 228,knurling 229 may be provided to facilitate rotation. Once connected tocover tube 182, rotation of knob 228 causes the distal working end ofthe instrument to rotate.

Referring now to FIGS. 4 and 19-27, there is illustrated an anvil 230and cartridge assembly, shown generally at 232, in accordance with oneembodiment of the present invention. Anvil 230 is an elongated piecewhich is mounted in support 214 by means of proximal legs 250. At itsdistal end, anvil 230 has an anvil plate 236 with a tissue contactingsurface 238 having staple forming depressions 240 (See FIG. 19). At itsproximal end, anvil 230 is provided with an upper camming surface 242and locking surface 244, which surfaces are engagable with correspondingtop arcuate camming surface 246 formed in forward collar tube 222.Transverse opposing projections 248 are formed on legs 250 at theproximal end of anvil 230 and provide an engagement point for anvil 230to be cammed between an open and closed position by the interaction ofcamming surface 242, locking surface 244 and top arcuate camming surface246 of collar tube 222. Preferably, the radius of curvature of the toparcuate camming surface 246 is shorter than the radius of curvature ofcamming surface 242 and equal to the radius of curvature of lockingsurface 244. This configuration prevents flexing of the camming surface246 of collar tube 222 and lateral movement of the anvil as it is beingcammed closed.

Anvil plate 230 also has a longitudinal center groove 252 to permitpassage of a knife 254. Anvil 230 is further provided with parallelaligning surfaces 256 positioned below camming surface 242. Thesealigning surfaces are dimensioned to fit outside projections 258 oncartridge housing 260 upon closure of the anvil 230. The engagement ofthe aligning surfaces 256 and the corresponding projections 258 ofcartridge housing 260 serves to more accurately and securely align anvil230 and cartridge housing 260 upon closure. Further visual confirmationof alignment is facilitated by a pair of parallel longitudinalindentations 262 formed in the distal end of anvil 230. Theseindentations 262 allow the surgeon to view the closed structure of theanvil 230 and cartridge assembly 232 to confirm accurate longitudinalalignment thereof.

Further, as shown in FIG. 21, the horizontal plane formed by tissuecontacting surface 238 intersects the horizontal plane formed by thecamming portion of the proximal end of anvil 230 at an obtuse angle "a".This angular orientation pre-cambers the anvil 230 and balances theclosure force applied by the anvil 230 to the captured tissue.

First and second camming surfaces, 264 and 266 respectively, are formedin a sidewall portion of the proximal end of anvil 230. These cammingsurfaces engage camming bosses, 268 and 270 respectively, formed oninner opposing sidewalls of collar tube assembly 220. Anvil 230 isinserted into collar tube assembly 220 and projections 248 engage withsupport structure 214 bring camming surfaces 264 and 266 into engagablealignment with camming bosses 268 and 270. Cartridge assembly 232,discussed in greater detail hereinbelow, is fixedly inserted into collartube assembly 220 and remains stationary relative to anvil 230.

During fabrication of anvil 230, the anvil blank may advantageously beformed by metal injection molding and thereafter coined and coated asdescribed below. A wide variety of staples and fasteners arecontemplated for use with the present apparatus. In a preferredembodiment for use with titanium fasteners, it has been found thatforming of the fasteners in the staple forming depressions 240 isfacilitated by applying a hard, relatively smooth surface on the stapleforming portion of the anvil 230. The preferred method of application ofthis surface is by electroless plating, with the surface being formed ofa metallic alloy such as, for example, nickel, gold, silver, titaniumnitride or chromium. Where nickel is used, the applied surface ispreferably in the range of 100μ-2000μ in thickness with an optimumthickness of between 200μ-500μ. Ranges for other alloy may varydepending upon their inherent characteristics.

Where nickel is to be applied, the preferred method is an electrolessplating method including the steps of: electrocleaning the anvil in acyanide-containing cleaner, reversing polarity at predeterminedintervals, preferably about every 10-15 seconds, at a current of about50 amps/ft² ; rinsing thoroughly; rinsing in a solution containing astrong acid, preferably 20% HCL, dipping several times; immersing theanvil in a NiCL strike tank for plating, preferably for two to fourminutes at a current of about 50 amps/ft² ; rinsing; and immersing theanvil in an electroless Ni bath, preferably Enthone 418 or 431, for atime sufficient to achieve the desired plating thickness. For example,at a deposition rate of 0.0005 in/hr, a time of between 30 to 40 minuteswould be required to achieve a thickness of about 300μ±50μ. Othercoating procedures are also contemplated including vapor deposition,etc. and are encompassed by the present invention.

Turning now to FIGS. 4 and 22-27, there is illustrated a replaceablecartridge assembly 232. The cartridge assembly 232 includes: a cartridgehousing 260; a cartridge 272 having a plurality of pushers 274 andstaples 276 disposed in longitudinal arrangement therein; and aplurality of cam bars 278 removably disposed in cam bar adaptor 280 anda cam bar alignment tab 282 as well as a knife 254 mounted in the cambar adaptor 280.

Referring specifically to FIGS. 25-27, the proximal end of cartridgehousing 260 comprises a substantially elongate channel of semi-circularcross-section having a forward and rearward portion 284 and 286respectively. A transverse locking slot 288 is formed in rearwardportion 286 and serves to engage and retain support structure 214. Uponinsertion into collar tube assembly, the forward end of supportstructure 214 is biased by the rearward portion 286 of cartridge housing260 until the support structure 214 engages locking slot 288.

Rearward projection 290 is formed in the base of cartridge housing 260.The function of this projection 290 will be described in greater detailbelow. Forward of the projection 290 is a bore 292 which receives shearpin 294 formed on cam bar adaptor 280 (FIGS. 22-24). A pair of crimps296 is provided in opposing sidewalls of the rearward portion of theproximal end of the cartridge housing. These crimps 296 provide afriction fit with cam bar adaptor 280.

The forward portion 284 of the proximal end of cartridge housing 260 hasprojections 258 which, upon closure of the cartridge assembly 232 andanvil 230, contact and align with anvil aligning surfaces 256 asdescribed above.

The distal end of the cartridge housing 260 comprises a channelstructure of substantially rectangular cross-section. This distal endconstitutes the cartridge receiving portion and is dimensioned toreceive cartridge 272 therein. Bores 298 and projection 300 serve toengage pins and bores respective in the cartridge 272 so as to align andretain the cartridge 272 within the cartridge receiving portion of thecartridge housing 260.

Referring to FIG. 26, the cartridge receiving portion in the distal endof cartridge housing 260 and the proximal end of cartridge housing 260are joined at an obtuse angle θ by the intersection of the horizontalplanes of both the proximal and distal ends of the cartridge housing260. This angular orientation serves to pre-camber the cartridgeassembly and facilitates accurate closure and alignment of the jawelements as well as more secure retention of subject tissue.

The cartridge 272 includes longitudinal groove structure 302 forreceiving and guiding knife 254 and a plurality of pushers 274 abuttingstaples 276. The staples 276 are advantageously arranged in sixlongitudinal rows with three rows positioned on either side of groovestructure 302.

Two pairs of longitudinal slots are formed in the cartridge housing 260and are adapted to receive a pair of double cam bars 278 therein. Eachpair of cam bars serving to drive three corresponding longitudinal rowsof staples. Further, the two pairs of longitudinal slots extend to theend of cartridge 232.

Cam bars 278 are providing with a cam surface 304 in an upper distal endthereof and an overhanging ledge 306 with vertical surface 308 in alower distal end. This overhanging ledge 306 is dimensioned to extendinto the longitudinal slots to a point wherein the vertical surface 308of the overhanging ledge 306 drops down and abuts the forward edge 310of the cartridge retaining portion of the cartridge housing 260 when thecam bars 278 move to their distal fired position. At their proximal end,cam bars 278 are provided with hook structure 312 for releasablyengaging cam bar adaptor 280.

Referring now to FIGS. 22-24, there are shown multiple views of the cambar adaptor 280. The cam bar adaptor 280 comprises a forward section 314and a rearward section 316. The forward section 314 is substantiallyrectangular in shape and has a central longitudinal groove 318 formedtherein and dimensioned to receive the longitudinal groove structure 302therein when the cam bar adaptor is urged to its forwardmost position.Flanges 320 and shelves 322 serve to removably retain the proximal endof cam bars 278.

The rearward section 316 is rectangular in shape with projections 324formed in the proximal end thereof. The rearward section is dimensionedto be receivable within the slot formed in fork 194 in channel 192. Theprojections 324 are dimensioned to engage ramping surface 198 to allowthe fork 194 to ride up and over the projections 324 when the fork 194is moved in the distal direction.

Vertical bore 326 and longitudinal groove 328 are formed in the rearwardsection 316 and serve to retain and hold the shank of knife 254. Shearpin 294 is integrally formed with cam bar adaptor 280 on a bottomsurface thereof and, in the prefiring position, is aligned with andreceivable into bore 292. Also, in this prefiring position, the rearwardsection 316 of the cam bar adaptor 280 is disposed over rearwardprojection 290 to effectively shield engagement of abutting structure202 with projection 290.

Turning now to FIGS. 28-34, there is shown a second anvil and cartridgeassembly. Referring to FIGS. 28 and 29, the cartridge assembly 330comprises a cartridge housing 332 mounting a cartridge 334 containing aplurality of pushers 336 disposed beneath staples 338, in a distal endthereof. A pair of cam bars 340 are positioned in the cartridge housing332 and are adapted to move longitudinally through parallel longitudinalslots formed in cartridge 334. A camming surface 342 is formed on anupper distal end of cam bars 340 with an overhanging ledge 344 formed ona lower distal end. Vertical ledge 346 is formed proximal to overhangingledge 344 and is adapted to engage the distal end of cartridge housing332 when the cam bars 340 are driven to their full distal position. Acam bar alignment tab 348 engages both cam bars 340 and holds them inparallel alignment. A cam bar adaptor 350 is adapted to fixedly receivethe shank portion of cam bars 340. Cartridge 334 is designed with threelongitudinal rows of staples with each row of staples being offset fromadjacent rows as shown in FIG. 28.

Referring to FIGS. 30-31, an anvil 352 is shown having substantially thesame design as anvil 230 described hereinabove. The primary differenceis that the distal portion 354 of anvil 352 is narrowed to receive andform three longitudinal rows of staples in contrast to the six rows ofstaples and knife accommodated by anvil 230. Anvil 352 includes a pairof longitudinally extending parallel legs 356 having transverse opposingprojections 358. Parallel aligning surfaces 360 are formed in sidewallsof anvil 352 and serve to overfit and align anvil 352 on cartridgehousing 332. First and second camming surfaces 362, 364 are formed insidewalls of anvil 352 proximal to parallel aligning surfaces 360 andserve to engage camming bosses 268, 270 formed in forward collar tube222 and rear collar tube 224, respectively.

Upper camming surface 366 is formed on an upper surface of anvil 352proximal to distal end 354 with locking surface 368 formed distallyadjacent upper camming surface 366. Both the upper camming surface 366and the locking surface 368 are adapted to engage and be cammed by toparcuate camming surface 246 formed in the distal end of forward collartube 222.

FIGS. 35-39 show a further surgical instrument similar to that shown inFIGS. 1-15 with the jaw structure of FIGS. 28-34. Referring to FIGS.35-36, the handle portion of this embodiment further includes annularseals 101, 103 provided between the distal end of frame 52 and theproximal end of cover tube 182. These seals serve to further inhibit theescape of insufflation gas from the operative site. Seals 107 and 109are positioned adjacent the proximal and distal ends, respectively, ofclamp tube 70 to better seal off insufflation gas from the area of thepiston 104.

A counter mechanism is also disposed in handle portion 52 and comprisesa counter ratchet 400 attached to trigger rod 112 and a leaf spring 402mounted in housing 66 so as to engage the teeth on the bottom surface ofcounter ratchet 400. Numerical indicators are longitudinally disposed onan outer surface of the counter ratchet 400 and correspond to the numberof times the instrument has been fired. An access plate 404 having aviewing window 406 therein is positioned in the outside surface ofhousing 66.

In operation, each time the instrument is fired the leaf spring 402engages a respective proximally located tooth of the counter ratchet400, effectively sliding the counter ratchet 400 distally to align thenext lower number in viewing window 406. The counter mechanism of thisembodiment further includes a locking feature whereby the trigger button96 is retained in the fired position when the leaf spring 402 engagesthe most proximal surface of the counter ratchet 400 and prevents thefiring rod 112 from returning to its proximal unfired position.

This instrument further includes an integral trigger button rotarysafety mechanism comprising a rotary safety shaft 408 disposed within aroller 410. The rotary safety mechanism is rotatably positioned intrigger button 96 with the roller 410 extending out beyond the plane ofthe back surface of trigger button 96. Projections 412 are eccentricallyformed on both sides of rotary safety shaft 408 and extend out beyondthe plane of the side surfaces of the trigger button 96. Spring 414serves to normally bias the rotary safety mechanism with the projections412 disposed in their distalmost orientation.

Referring now to FIGS. 38 and 39, in the instrument's unfired position(FIG. 38) projections 412 are in their distalmost position and aredisposed in direct alignment with the proximal ends of the housingmembers 64, 66. In this position, the trigger button 96 cannot beaccidentally depressed to fare the instrument In order to disengage thesafety mechanism, the roller 410 is moved in the direction of arrow 416which serves to rotate projections 412 from their distalmost position(FIG. 38) to their proximalmost position (FIG. 39) effectively allowingtrigger button 96 to be depressed to fire the instrument. As soon asroller 410 is released, spring 414 returns the safety mechanism to itsnormal position to prevent subsequent accidental firings.

FIG. 37 shows the endoscopic portion and the jaw portion of the surgicalapparatus of FIG. 35. The anvil 418 of this embodiment is provided witha pair of angled proximal legs 420. This feature permits the anvil 418to be opened wider to more easily receive tissue between the anvil 418and cartridge 58. The angled proximal legs 420 preferably extend at anangle of between 0° and 30° from the longitudinal plane of the anvil.

A clamp lockout structure is shown in detail in FIGS. 37, 40 and 41incorporated into the support structure 214 and upper extension spacer210. The clamp lockout structure comprises a leaf spring 430 having adiagonally downwardly extending projection 432 attached thereto. A slot434 is formed through the top surface of support structure 214 and isadapted to engage and receive projection 432 whenever the supportstructure is not longitudinally aligned. This clamp lockout structure isdesigned and configured to prevent the instrument jaws from closing ontissue unless the cartridge and/or jaw elements are properly emplacedwithin the apparatus.

In operation in the stapling apparatus of FIG. 37, leaf spring 430 andprojection 432 are normally disposed above support structure 214. Theproximal ends of the cartridge 334 and the anvil 418 are insertedthrough collar tube 222 and brought into engagement with the distal endof support structure 214. (See FIG. 40) In the event that the cartridge334 and/or the anvil 418 are not properly and/or completely insertedinto engagement with support structure 214, the resulting angulardisposition of the support structure 214 brings slot 434 into alignmentwith projection 432. (See FIG. 41) As the operator attempts to depressthe handle 62, the extension spacer 210 begins to move distally causingprojection 432 to enter slot 434 and become entrapped thereineffectively preventing any further distal movement of the extensionspacer 210 and, in turn, preventing approximation of the anvil 418 andthe cartridge 334.

In use, the endoscopic portion of the instrument is inserted into thebody, preferably through an endoscopic tube. It is further preferredthat the endoscopic tube apparatus be capable of maintaining a sealedpneumoperitoneum, with the internal sealing member of the housingfurther maintaining this seal despite introduction of the instrument inaccordance with the invention into the endoscopic tube. As a practicalmatter, the jaws of the instrument are closed for insertion into theendoscopic tube, either by pinching the anvil and cartridge prior toinsertion or by closing the articulating handle to cam the jaws closedprior to insertion.

After insertion into the endoscopic tube, the endoscopic portion may berotated in order to appropriately orient the instrument at the staplingsite. Rotation of the endoscopic portion relative to the body may beattained by rotating the instrument, as a whole, by rotating theendoscopic portion relative to the frame using rotation knob 228 (SeeFIG. 1), or by a combination thereof.

Referring to FIGS. 3, 5-8 and 32-34, with the instrument properlyoriented so that the tissue to be fastened is disposed between the openjaws of the instrument, i.e., between the tissue contacting surfaces ofanvil member 230 and cartridge 302, the jaws are closed to clamp thetissue. In the first embodiment, the surgeon presses down on actuatinghandle 62, thereby sliding collar tube assembly 220 distally, via clamptube 70, extension sleeve 204, and extension spacers 210, 212.

Referring to FIGS. 32-34, as collar tube assembly 220 moves distally inthe direction of arrow A from a first position where the top arcuatecamming surface 246 at the distal end of forward collar tube 222 isproximal to camming surface 242, (FIGS. 32-33), to a second positionwhere the top arcuate camming surface 246 is engaged with lockingsurface 244, (FIG. 34), the top arcuate camming surface 246 contacts thecamming surface of the anvil, thereby forcing the anvil to cam viacamming surfaces 264, 266 on camming bosses 268, 270 until the anvil isbrought into close cooperative alignment with the cartridge assembly.FIG. 34 illustrates the instrument with the jaws in a closed position.

After closing the instrument jaws, the instrument is ready to be fired.When the surgeon is ready to emplace the staples and cut tissue, firingtrigger 96 is depressed to actuate the pneumatic actuator 98 asdiscussed in detail above. Piston 104, attached to the proximal end ofchannel 192 is driven distally causing camming surface of forks 194 toride up and over projection 324 of the cam bar adaptor 280 and drive thecam bar adaptor in a distal direction. Shear pin 294 is severed and thecam bars and knife are driven longitudinally through the cartridge tosequentially drive and form staples and cut tissue.

As piston 104 contacts return springs 140, 142, pusher washers 186 arecompressed on themselves and serve to store energy as the piston movesdistally toward the cartridge assembly. This initial compression occursin the range of between about 20 p.s.i. to about 150 p.s.i. andpreferably within a range of about 30 p.s.i. to about 60 p.s.i. Near theend of the distal stroke of the piston 104, this stored energy isreleased to drive the cam bars 278 through the final distal limits oftheir navel within the longitudinal slots in the cartridge. At thedistal extreme of the longitudinal stroke, the overhanging ledges 306 ofcam bars 278 drop over the edge of the cartridge housing thus abuttingvertical surface 308 with edge 310.

After firing, return springs 140, 142 engage piston 104 and return it toits original position. The return motion of piston 104 causes rockinglever 120 to be cammed aside by camming surface 144 of piston 104. Inthe embodiment containing knife 254 discussed above, the cam bars 278are pulled out of cam bar adaptor 280 and remain in position in thelongitudinal slots of the cartridge 334. The cam bar adaptor, with knife254 attached, moves proximally within cartridge housing 272 until theouter edges of cam bar adaptor 280 impinge on crimps 296.

The cam bar adaptor 280 is held in place by crimps 296 while cammingsurface 200 of fork 194 causes the fork to ride up and disengage withprojection 324 of the cam bar adaptor. Channel 192 continues to move inthe proximal direction until abutting structure 202 is positionedproximally to rearward projection 290 formed in the floor of cartridgehousing 260. At this point, the entire cartridge assembly 232 isdeactivated.

In the event that the surgeon should accidentally attempt to again firethe instrument without replacing the deactivated cartridge with a newunfired cartridge, the resulting distal longitudinal motion of thechannel 192 moves abutting structure 202 into contact with rearwardprojection 290 effectively preventing further movement of forks 194toward cam bar adaptor 280.

After firing, articulating handle 62 is raised with the assistance ofhandle return spring 82 which action retracts collar tube assembly 220.This retraction causes anvil 230 to cam out of engagement with cartridgeassembly 232. Similarly, raising of articulating handle 62 causes camslide 124 to move upward disengaging the pneumatic firing mechanism.

In order to replace the cartridge assembly, the instrument is withdrawnfrom the patient. The cartridge assembly is released and may be removedby pulling it distally out of collar tube assembly 222.

To reinsert a new cartridge assembly, the proximal end of the cartridgeassembly is inserted into collar tube assembly 222 until engaging andlocking into support structure 214. The instrument is now ready forreinsertion and continued use.

Operation of the instrument with the cartridge and anvil assembly shownin FIGS. 28-31 is substantially similar to that described above. Tubulartissue to be ligated and/or divided is captured within the anvil 352 andthe cartridge assembly 330 such that the tissue is transversely orientedtherebetween. The cartridge assembly 330 and anvil 352 are approximatedby means of camming surfaces 362, 364 and camming bosses 268, 270, asdescribed above. The staples 338 are fired, ligating the tissue.

Unlike the instrument described previously, the cartridge assembly 330does not include a knife and therefore does not require that the cambars be retracted by channel 192. In operation, the distal end ofchannel 192 engages the proximal end of cam bar adaptor 350 and drivescam bars 340 to their extreme distal position (FIG. 34). In thatposition, overhanging ledges 344 drop over the distal end of cartridgehousing 332 and remain there. As the piston 104 retracts, channel 192moves away from cam bar adaptor 350 and retracts to a position proximalto rearward project 290, this leaving cam bars 340 and cam bar retainer350 in the distal position within cartridge assembly 332. Opening,removal and replacement of the deactivated cartridge are effected insubstantially the same way as described above with respect to the secondalternative embodiment.

Referring to FIGS. 42-45, there is illustrated a unique countermechanism which is designated generally by reference numeral 450.Counter mechanism 450 is operatively associated with actuation trigger96 and is configured to visually indicate to the user the number oftimes the surgical apparatus of the subject invention may be fired, andto prevent the operation of the pneumatic actuation system 68 after apredetermined number of firings. This effectively prevents the apparatusfrom being fired when there may be an insufficient quantity ofcompressed gas contained within gas Supply canister 88.

In brief, as illustrated in FIG. 42, the counter mechanism 450 of thesubject invention includes a spring biased indexing shaft 452 having arather tooth 454 formed at the proximal end thereof for interacting witha linear rack member 456. The indexing shaft 452 extends proximally froman indexing block 458 which is slidably mounted on a rail 460. The railis connected to a bracket 462 which is mounted to the inner surface ofhousing member 66. A coiled compression spring 464 is also mounted onrail 460, distal to the indexing block 458, for biasing the indexingblock 458 in a proximal direction. The indexing block 458 is dimensionedand configured to interact with piston 104 as it travels in a distaldirection when the surgical apparatus is operated. In particular, aflange 104a depends outwardly from the piston 104, adjacent the pistonhead 104b, for contacting the indexing block 458 as the piston 104advances toward the distal end portion of handle 62, as illustrated inFIG. 43, to index the rack member 456 to the position illustrated inFIG. 44.

With continued reference to FIG. 42, the rack member 456 includes anupper set of five ramped engagement notches 466a-466e and a lower set offive corresponding ramped engagement notches 468a-468e. The ratchettooth 454 interacts with the upper set of engagement notches toincrementally advance the rack member 456 each time the apparatus isfired, and a leaf spring 470 interacts with the lower set of engagementnotches of rack member 456 for sequentially maintaining the rack member456 in an incrementally indexed position.

Numerical indicia are imprinted on the outside surface of rack member456 and are sequentially visible through a windowed porthole 472provided in the side wall of handle 62. The numerical indicia correspondto the five engagement notches 466a-466e defined on rack member 456. Inparticular, notches 466a-466e correspond to the numerals "4-0",respectively. Each numeral identifies the number of times the pneumaticactuation system 68 may be actuated to operate the surgical apparatus ofthe subject invention. One skilled in the art will readily appreciatethat, depending upon the volume of gas needed for actuation, and/or thevolume of the supply container, the number of engagement notches formedon rack member 456 can be increased or decreased.

Rack member 456 is dimensioned and configured to interact with thetrigger rod 112 which extends from the trigger 96. More particularly, ablocking tab 112a depends outwardly from the trigger rod 112. Theblocking tab 112a is dimensioned and configured for engagement within acorresponding reception notch 474 formed in housing 66 of the surgicalapparatus. In use, when the apparatus is fired for the fourth and finaltime, the indexing shaft 452 will index the rack member 456 to thedistal-most position illustrated in FIG. 45. At such a time, the rackmember 456 will urge the blocking tab 112a into the reception notch 474.As a result, the trigger rod 112 will be maintained in a distal positionand, as a consequence, further user actuation of trigger 96 will beinhibited.

In another embodiment of the subject invention which is illustrated inFIGS. 46 and 47, there is provided a modified lockout mechanism whichprevents the instrument from being fired unless an unfired cartridgeassembly has been correctly inserted into the instrument. Specifically,a channel stop 480 is affixed to an underside of channel member 192,preferably by welding or, alternatively, may be integrally formed inchannel member 192. A lower extension sleeve return stop 482 is affixedto lower extension spacer 212 and is configured and dimensioned, asdescribed hereinbelow, to interact with channel stop 480.

Upon loading a cartridge assembly, such as cartridge assembly 60, forexample, opposed ramping surfaces 198 and 200 on forks 194 of channelmember 192 ride up and over the angled face 484 of cam bar adaptor 280(FIG. 46). After the instrument has been fired, channel member 192returns with piston 104 in a proximal direction to disengage from cambar adaptor 280. As shown specifically in FIG. 47, as channel member 192returns proximally, channel stop 480 abuts lower extension sleeve returnstop 482, thereby preventing the complete return of piston 104 andchannel member 192 to an original prefired position.

Referring now to FIGS. 48 and 49, the trigger rod 112 of this embodimentis structurally modified to include a distally facing projection 112band a modified rocking lever 486. The rocking lever 486 includes anarcuate groove 488 at a lower end portion thereof for engagement with arocking lever stop 490, as shown in FIG. 48, which is affixed to aninside surface of housing member 66.

As noted above with respect to the previously described embodiments ofthe invention, in operation, when trigger 96 is pushed distally, triggerrod 112 translates distally to engage transverse projection 120 onpiston slide 114 of piston 104. As piston slide 114 is driven forward,it pivots the modified rocking lever 486, which, in turn, actuates thepneumatic actuation system 68 to drive piston 104 forward to ejectstaples from the cartridge assembly 60.

As piston 104 advances in a distal direction, the top surface of themodified rocking lever 486 rides beneath piston 104. As shown, forexample in FIGS. 5 and 7, when piston 104, has been fully fired, themodified rocker lever 486 enters a gap 138 in piston 104, allowingrocking lever 486 to pivot back to stop the flow of gas from cylinder88. Initially, when piston 104 begins to return proximally, a cammingsurface 144 in gap 148 biases rocker lever 486 transversely, against thebias of spring 144. As piston 104 continues to return in a proximaldirection, rocking lever 486 rides along a side edge of piston 104. Inthe embodiments described hereinabove, in a return stroke, the piston104 would fully return to a point where the piston slide 114 would bedisposed proximal of rocking lever 486, permitting the rocking lever 486to translate rearwardly against the bias of spring 144. However, in thepresent embodiment of the subject invention, piston 104 is preventedfrom fully returning since lower extension sleeve return stop 482engages the channel stop 480 on channel member 192 preventing the fullreturn of piston 104.

As shown in FIG. 48, rocking lever 486 is maintained in a laterallydisplaced position compressing spring 144 transversely. In this positionrocking lever 486 engages rocking lever stop 490 and is prevented frompivoting. Should the user attempt to depress the trigger 96, projection112b on trigger rod 112 will abut the modified rocking lever 486. Sinceprojection 112b abuts the modified rocking lever 486, upon depression oftrigger 96, the distal end of trigger rod 112 is prevented fromadvancing distally and cannot engage the transverse projection 120 ofpiston slide 114. In this manner, the trigger mechanism is "locked out"and disabled from firing. Once a new fully loaded cartridge assembly hasbeen inserted into the instrument, the opposed ramping surfaces 198 and200 of forks 194 on channel member 192 ride up and over the sloped faces484 of cam member 280. As a result, channel stop 480 is lifted out ofengagement with lower extension sleeve return stop 482 allowing thepiston 104 to fully reset, as shown in FIG. 49.

In sum, after firing the instrument, piston 104 will be prevented fromfully resetting due to the orientation of channel stop member 480, andthe modified rocking lever 486 will be maintained out of alignment withthe piston slide 114 and prevented from pivoting by rocking lever stop490. In addition, projection 112b on trigger rod 112 engages or abutsmodified rocking lever 486, thus preventing the distal end of triggerrod 112 from engaging transverse projection 120 on piston slide 124. Asa result, the device is disabled until a new fully loaded cartridge hasbeen inserted.

Referring to FIG. 50 in conjunction with FIGS. 46 and 47, in amodification of the previously described embodiment, there is alsoprovided a cartridge identification adaptor which comprises a transversebridge 490 formed between forks 194 of channel member 192. Bridge 490serves to prevent a cartridge having incompatible firingcharacteristics, but which would otherwise be loadable into theinstrument, from firing. This is desirable to prevent firing of acartridge having characteristics, such as, for example, length of cambar travel, number of staples, presence or absence of a knife member,etc., in an instrument whose actuation system, i.e. gas pressure andlength of piston stroke, or anvil design/layout would otherwise beincompatible. This feature, i.e., the cartridge identification feature,is equally advantageous in surgical instruments that are manuallyactuable as in pneumatically actuated instruments. As shown in FIG. 46,bridge 490 is dimensioned and configured to clear cam bar adaptor 280and thereby identify a fastener cartridge compatible with the pneumaticactuation system 68 and/or anvil configuration of the subjectinstrument.

Referring to FIG. 50, if an unfired incompatible cartridge is loadedinto the instrument, bridge 490 would engage a distal end of anincompatible cam bar adaptor 492 and drive the cam bar adaptor 492forward into the incompatible cartridge as the cartridge is inserted.This distal movement of the adaptor 492 causes the cartridgeidentification structure to recognize the incompatible cartridge as a"fired" cartridge. Specifically, incompatible cam bar adaptor does nothave angled projections as shown in FIG. 50. In this manner, the opposedramping surfaces 198 and 200 on channel member 192 do not engage angledprojections on the incompatible cam bar adaptor 492 of the incompatiblecartridge.

Upon insertion of a compatible cartridge into the device, opposedramping surfaces 198 and 200 on channel member 192 will ride up and overangled projections 484 (see FIG. 46) on the compatible cam bar adaptor280, raising channel stop 480 out of engagement with lower extensionsleeve return stop 482, and thereby allowing piston 104 to fully resetthus enabling the instrument to be fired. In this manner, bridge 490serves as an identifier to identify a compatible cartridge to be firedin the instrument.

Thus, for example, cartridges which include six rows of staples and aknife intermediate the two centermost staple lines, i.e., an Endo GIA*staple cartridge manufactured by the present assignee, would be acompatible cartridge for an Endo GIA* instrument whose anvil includessix corresponding staple depressions and a knife channel. By contrast,however, an Endo TA* staple cartridge, also manufactured by the presentassignee, which includes three staple rows and no knife blade, would bean incompatible cartridge for the Endo GIA* instrument.

It will be understood that various modifications can be made to thevarious embodiments of the present invention herein disclosed withoutdeparting from the spirit and scope thereof. For example, various sizesof the instrument are contemplated, as well as various types ofconstruction materials. Also, various modifications may be made in theconfiguration of the parts. For example, in the first embodiment theelongated slot for allowing access to the thumbwheel may be placedalternatively in the left body portion or right body portion. Thereforethe above description should not be construed as imitating the inventionbut merely as exemplifications of preferred embodiments thereof. Thoseskilled in the art will envision other modifications within the scopeand spirit of the present invention as defined by the claims appendedhereto.

What is claimed is:
 1. A surgical apparatus for driving surgicalfasteners comprising:a) a frame portion; b) an elongated body portionextending distally from said frame portion; c) a fastener applyingassembly operatively associated with a distal end portion of said bodyportion and including:i) a compatible cartridge member removablymountable in said distal end portion and having a plurality of surgicalfasteners disposed therein, said compatible cartridge member having afirst predetermined set of firing characteristics; and ii) an anvilmember mounted adjacent said compatible cartridge member and againstwhich said fasteners are driven when ejected from said compatiblecartridge member, said anvil member configured to correspond to saidfirst predetermined set of firing characteristics; d) fastener ejectionmeans actuable from said frame portion for sequentially ejecting saidplurality of surgical fasteners from said compatible cartridge member;and e) identification means associated with said fastener ejection meansfor permitting actuation thereof when said compatible cartridge isinserted within said distal end portion and for preventing actuationthereof when an incompatible cartridge member having fasteners disposedtherein and having a second set of predetermined firing characteristicsdifferent from the first predetermined set of firing characteristics isinserted within said distal end portion of said body portion.
 2. Theapparatus as recited in claim 1, wherein said identification means is atransverse bridge member associated with said fastener ejection meansand configured to disable said incompatible cartridge member uponengagement with a portion of said incompatible cartridge member.
 3. Theapparatus as recited in claim 2, wherein said fastener ejection meanshas a channel member and said bridge is formed on said channel member.4. The apparatus as recited in claim 1, wherein said incompatiblecartridge does not include ramping structure which is present on acompatible cartridge member.
 5. The apparatus as recited in claim 1,further comprising a pneumatic actuation system disposed within saidframe portion and operatively associated with said fastener ejectionmeans.
 6. A surgical apparatus for driving surgical fastenerscomprising:a) a frame portion; b) an elongated body portion extendingdistally from said frame portion; c) a fastener applying assemblyoperatively associated with a distal end portion of said body portionand including:i) a compatible cartridge member removably mountable insaid distal end portion and having a plurality of surgical fastenersdisposed therein, said compatible cartridge member having a firstpredetermined set of firing characteristics; and ii) an anvil membermounted adjacent said compatible cartridge member and against which saidfasteners are driven when ejected from said compatible cartridge member,said anvil member configured to correspond to said first predeterminedset of firing characteristics; d) a channel member actuable from saidframe portion, said channel member movable relative to said elongatedbody portion to sequentially eject said plurality of surgical fastenersfrom said compatible cartridge member; and e) identification meansassociated with said channel member for permitting actuation thereofwhen said compatible cartridge is inserted within said distal endportion and for preventing actuation thereof when an incompatiblecartridge member having fasteners disposed therein and having a secondset of predetermined firing characteristics different from the firstpredetermined set of firing characteristics is inserted within saiddistal end portion of said body portion.